1. Field of the Invention
The present invention relates to a paper-sheet punching device that punches a hole in a paper sheet.
2. Description of the Related Art
Japanese Patent Laid-Open Publication No. S62-32798 discloses a conventional punching device that punches holes in a copy paper-sheet, which is a copy of an original paper-sheet, after the copy paper-sheet is discharged from a copying machine. The punching device includes a positioning plate for positioning the copy paper-sheet, a punch that punches holes in the copy paper-sheet, a die provided at a position opposite to the punch so as to sandwich the paper sheet in association with the punch, and a paper sheet pressing plate that presses the copy paper-sheet while the punch punches holes in the copy paper-sheet so that the copy paper-sheet does not move. The copy paper-sheet with the holes passes through a nip between the punch and the die and is conveyed downstream.
In the conventional punching device, thus, it is necessary to secure a nip having a sufficient width between the punch and the die in consideration of the thickness of the paper sheet so that a stroke of the punch becomes longer. A longer stroke has a greater chance of punching irregular holes than a shorter stroke.